US3596472A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for liquefying natural gas containing nitrogen
Assignee: Messer Griesheim GmbH
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Filing: 1968-12-16
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Granted: 1971-08-03
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Expires: 1988-12-16
Abstract
Abstract Natural gas containing nitrogen is cooled and liquefied by a cascade system having two closed refrigeration circuits operating on multicomponent refrigerant mixtures. The liquefied gas is distilled into three fractions: nitrogen, a mixture of nitrogen and methane, and liquid natural gas substantially free of nitrogen. The mixture of nitrogen and methane provides the refrigerant in a third and coldest open circuit of the cascade system to subcool the liquid natural gas to storage temperature.
Inventors
- 👤 Martin Streich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:14
CPC Classifications
F; F25; F25J; F25J1/00; F25J1/02; F25J1/0211; F25J1/0217; F25J1/0218; F25J1/0002; F25J1/0022; F25J1/003; F25J1/0032; F25J1/004; F25J1/0045; F25J1/0047; F25J1/0052; F25J1/006; F25J1/007; F25J1/0072; F25J1/0214; F25J1/0219; F25J3/00; F25J3/02; F25J3/0204; F25J3/0209; F25J3/0228; F25J3/0233; F25J3/0257; F25J2200/00; F25J2200/02; F25J2200/50; F25J2200/74; F25J2200/90; F25J2200/94; F25J2270/00; F25J2270/12; F25J2270/42; F25J2270/60; F25J2290/00; F25J2290/34; Y; Y10; Y10S; Y10S62/00; Y10S62/927
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
45 words
The process of claim 1 wherein the refrigerant mixture of the third circuit, upon being expanded, flows through a heat exchange passage in the top portion of the rectifying zone to condense vapor in said top portion and thus provide reflux for said rectifying zone.
Claim 2
Dependent Claim
55 words
The process of claim 1 wherein the multicomponent refrigerant mixture of the coldeR of the two closed refrigeration circuits flows through a heat exchange passage in the bottom portion of the rectifying zone and, after being expanded, subcools liquefied natural gas substantially free of nitrogen which is withdrawn from the bottom of said rectifying zone.
Claim 3
Dependent Claim
57 words
The process of claim 1 wherein substantially pure nitrogen is withdrawn from the top of the rectifying zone and is passed in countercurrent heat exchange with the liquefied natural gas substantially free of nitrogen withdrawn from the bottom of said rectifying zone and with the natural gas containing nitrogen prior to its discharge into said rectifying zone.
Claim 4
Dependent Claim
30 words
The process of claim 1 wherein each of the two multicomponent refrigerant mixtures is expanded to a pressure higher than 2 atmospheres absolute but not exceeding about 5 atmospheres absolute.
Claim 5
Dependent Claim
24 words
The process of claim 1 wherein each of the two multicomponent refrigerant mixtures is made up of components of the natural gas containing nitrogen.
References Cited (Backward Citations)
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Cited
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US2960837A
Cited
US3218816A
Cited
US3254496A
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US3254495A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |